Pyrometer.



y 0.13. FOSTER.

PYROMET'ER. APPLIoATIoN FILED 11:13.10,` 1909.

Patented-Sept 7, T909.

Snowdon @mi fname:

to easier measurementythe amount .o f rays received from the hotbody being vhinlted so .To all .whom "it mcy-concern:

- UN 1TB-D STATES.

camas nimm restait 'or amuseren-'mw You.'

- `intitolaifi'rnii.

B e it'k'nown that I, Ci'iARnEsEnwiiv Fos- TER, ofRochester, in the county of Monroe and-Statev of New York, have l'invented cer.-

tain newand useful Improvements in Pyrometers; and I'do hereby declare the follow-' ing to be a'clear, full, and exact description of the same, referencebeing had to the accompanyingdrawings,forming a part of this specification, and to therefereiice-numerals marked thereon.

'nl he present invention relates to pyrome-f l ters and more particularlyto that type 4iii which lthe-radiant heat of a body is meas' ured without subjecting the pyrometer structureto' the actual temperature to be measured, an objectof the vinvention being to dispense with focusing operations or adjustments and'yet obtain a definite focusso that an accurate measurement may be obtained in a minimum space of time.'

'To-this and other eds the invention .con-

siste in certain improvements and combina! tions of parts all as'will be hereinafter more fully. described, the novel features being pointed outv inthe' claims'at'theend. of the specification.

In the drawings: Figure l is a longitudiiialfsectional view of one embodiment of the invention in which av concave mirror is em' ployed for projecting the rays onta thermoelectric couple;

-a-a, Fig. 1-;'Fig. 3 Ais-adetail perspective.

Fig. 2' isa "section on line Viewv of the thermdcouple and the guard therefor illustrated in Figs..1 and'2;'l1`ig. 4 is a longitudinal 'sectional'V view; of 'another embodiment of the invention; Fig. 5 is a section on' line b-b Fig. 4;- Fig. 6 is ade-1 sensitive device illustrated in Figs. 4 and 5; Fig; 7 is a lontail perspective View of the gitudinal section of another embodiment of the invention in whichthe sensitive device is y. theformfofv a mercurymr spirit thermome-- 4'5- ter';

and Fig. T8 is a longitudinal vsection of an embodiment'in Whichr the sensitive del- A vice is-ofset'in order not vto be affected by direct rays fromthe hot body.

The present invention is based upon the of the concentration of radiant concentrates it onto another surface' of relatively smaller area, `giving greater intensity andv herefore causing a larger rise in temperature ofthe small area which is subject a receiving surface 'which-in turn 'is in the forni of that th'e indicationsare independent bf the I distance between the hot body andthe re ceivi'ng surface.

A feature of. this invention is the provision of. aconst'ant and definite focus so thatthe usual' focusing device or eyepiecez tofgether with the focusing operations may be' dispensed with.' `This feature mayA be em" 65. l

bodied in various constructions, some of Specification of Letters Patent.. Paftenfed Spt, 1909, i' Appiication mea February 19,1909. vserial-im 4??,151.v J

eci

which are herein illustrated,- thatshown iii Figs. 1 -to S'employing' .a casing l'preferably of tubular form having an opening or. aperture Q'located in this instance at one end thereof. Carried by and arranged within the said casing is the sensitive device consisting of a thermo-electric couple Shaving at its junction a small heat receiving surface or plate 4. The outer ends of the 'thermoelectric couple maybe secured 'to' binding posts 5 which in turn may be connected to a measuring device 'such`a-s a potentiometer or a sensitve milli volt-nietei-,it of 'course'be- 111g un' enerate an E. M. F'. from the measurement o which the tempera-` ture of thehot body may be computed.

' In order'to concentrate the heat onltlic ployed an optical condenser inthe forni of a concave mirror casing opposite the aperture and having one of its omugate foci at the aperture and the other at the sensitive device. A guard shield 7 may be arranged in front of the thermo-electric coule so that the-latter is er'stood that the concentration of heat on th'eplate 4 will 'sensitive device, there isin this instance em- 4 6 located at that end of the subjected only to tie' radiation focused by the mirror 6 and is protected against direct rays vfrom thehot ,In theembodimcnt of theV invention shown in'Figs. 4, 5 and 6',the parts'a're. the same as shown in Figs. 1 to 3, exceptV that the seiisitivefdevice is-.inade up of two or more metals8 fastened together and rolled into volute form in such a manner that the in crease oftemperature will cause the curling diil'erentv thermocoeiicients of eirpansion.

A' pointer (riindex 9 projects through. the casing and travels over a'scale' l0 to indicate the temperature.

-in a partition 12.between 'theaperture and thesensitive device which is' in the form of leo up or urcurling of the spiral, due to the a spirit or mercury thermometer having the usual indications thereon..

Z or-rthe apex of the angle .'v, y, e, a distin-Y guishing device-such as a collar may be lo-n ln Fig. 8 a concave mirror 13 is arranged atan angle to the plane of the aperture and at the rear end vof the casing so as to -focus on a sensitive device located in a laterally oli'set pocket 14 in the casing, the pocket being provided to protect from direct radiation the sensitive device, which may be of the form shown in Figs. 1 to 3.

In using the present invention its aperture is directed 'toward the hot body represented by the line w-y, Fig. 1, the only condition being that the aperture be completely filled by the hot body as viewed from all points on thecondenser, and to thissend the diameter of the hot body :1J-y .must equal the base of the triangle sv, y, .e or any extension thereof. The triangle Vis determined by two Iintersecting lines drawn from two diametrically y opposite points at the perimeter of the condenser and. coinciding with two diametrically opposite points at the perimeter of the aperture. At the point of intersection cated on the exterior of the casing so thata user may determine Whether the instrument is located within the limits between which it must Abe positioned. The condition of the sensitive device is, of course, found from the indicator which gives either a direct reading of the temperature, as 'shown in Figs. 4 to 7,

or a reading from which the temperature may be computed as shown in Figs. 1 to 3 and 8. v

From the foregoing it will be seen that there has been rovided a pyrometer which need not be subjected to the temperature' of the hot body and which ha-s a constant Iand definite focus so that focusing devices or eyepieces are unnecessary, thus permitting the user to obtainV an accurate measurement of the temperature of a hot body in a minimum space of time.

I claim as my invention: v

l.. -In a pyrometer, the'combination with a` casing havmg an aperture therein, of a heat jugate foci at the aperture and the other at the sensitive device, and means for determining the amount that the sensitive device is ai'ected by the rays concentrated thereon by the condenser.A

3. In a pyrometer, the combination witha casingl having an aperture therein, of a heat sensitive device carried by thecasing in fixed direct rays from the hot body through the aperture, and au optical condenser fixed rel- I atively to the aperture and to the heat sensitive device and having one of a pair of its conjugate foci atthe aperture and the other at the sensitive device.

4. In.a pyrometer, the combination with a casing having ali' aperture therein, of a heat sensitive device carried by the casing in fixed relation to the aperture, an optical condenser iixedrelatively to the aperture and to the heat sensitive device, and having one of a pair of its conjugate foci at the aperture nd the (ller at the sensitlive device,l and e3 istini. 0' device' on t e cas' o' ocat in a p ne tilznsverse of the casinllgbwith the point of intersection of two lines drawn from diametrically opposite points at the perimeter of vthefcondenser and coinciding with two diametrically oppositepoints at the perimeter of the aperture.

CHARLES EDWIN FOSTER.

-VVitnessesz Bussum B. Glnrrrrn, HAnoLb H. Snnrs.

Vrelation to the aperture and protected from 

